John Gill and John Herron sued Steve Cannane and publisher HarperCollins over his 2016 book Fair Game.
The book covered the controversial religion’s role in uncovering the psychiatric scandal at the now notorious Chelmsford Hospital in NSW.
The doctors contended deep sleep therapy was accepted medical practice at the time and they were hung out to dry at a royal commission in 1990 after a Scientologist campaign.
Their version of events was rejected last year by Federal Court Justice Jayne Jagot, who criticised the attempt to “rewrite history” when it came to the “dangerous, experimental” treatment.
Dr Gill, who funded the proceedings, and Mr Herron, who has since died, leaving behind an insolvent estate, have appealed the decision to the full Federal Court.
Their barrister Bret Walker told a hearing before Justices Steven Rares, Michael Wigney and Michael Lee on Monday that Mr Cannane had failed to give Dr Gill and Dr Herron a chance to respond in chapters that referenced the then 26-year-old findings of the royal commission.
“The main thrust of your argument wasn’t that the royal commission report wasn’t authoritative, or that it wasn’t reasonable to rely on it as a source of information,” Justice Wigney said.
“But the main point was that it didn’t absolve him of the reasonable requirement of your clients as to what their position was.”
“That’s right,” Mr Walker responded.
“Ironically, it becomes so authoritative (through the passage of time) it’s not reasonable to ask somebody whether what is said in it is right. What do they have to say about it?”
Mr Walker also told the hearing that Justice Jagot was wrong to rely on evidence and statements made by his clients during the royal commission.
Section 17 of the Royal Commission Act says that “no answer made” by a witness can “be admissible in evidence against that person in any civil or criminal proceedings”.
“That is why, in a nutshell, most of the evidence used by her honour to dispose adversely of these proceedings against the appellants was wrong,” Mr Walker said.
The hearing continues.
HarperCollins is a subsidiary of News Corp, the publisher of NCA NewsWire.